William was the Coninghams' only child to survive infancy. His foster-brother was James Fitzjames, one of the leaders of the doomed Franklin Expedition; the parents treated James Fitzjames as if he was their own son and William regarded him as a brother.[3]

A keen correspondent, he exchanged a number of letters on spiritual matters with his cousin John Sterling. He was subsequently to edit and publish these as Twelve Letters in 1851.[1][6] He was also a friend of Thomas Carlyle, and a number of letters between the two survive.[7]

By late 1863 it became apparent that Coningham's health was deteriorating. In January of the next year he announced his immediate retirement from the Commons.[15][16] By 1868 his health had recovered and he attempted to regain his parliamentary seat at Brighton, standing as one of three Liberal candidates for the two seats in the constituency, but without success.[17]